1. Field of the Invention
This invention relates generally to communication systems, and, more particularly, to wireless communication systems.
2. Description of the Related Art
Wireless communication systems use a geographically dispersed network of base stations to provide wireless connectivity to large numbers of mobile units. The term “Node B” is used in 3G UMTS standards as the name for the base stations. The term “Evolved Node B (eNB)” is used in the 4G LTE (Long Term Evolution) standards as the name for the base stations that implement the 4G LTE standard. Unlike wired communication systems, the quality of a wireless communication link or connection is both geographically and temporally variable. Furthermore, the quality of service received by individual users is an important factor in determining customer satisfaction. Service providers can bill higher rates for guaranteed higher quality of service levels. Wireless operators like Verizon Wireless use data generated by the wireless communication system to assess the overall user experience in wireless communication systems. One approach is to use performance counters to generate statistical information related to the user experience. The performance counters typically gather statistical information to assess the performance of interfaces between elements of the wireless communication system and to assess the performance of the software implemented in these elements.
Another approach to monitoring the user experience is to collect performance data in near real time for each wireless user. One example of this type of information is Per-Connection Measurement Data (PCMD) that is used to capture statistics related to the user experience each time the wireless user accesses the network or performs other procedures. In proposed 4G wireless networks, the PCMD data is collected by different network elements. For example, eNodeBs (eNBs) may collect one type of PCMD data, mobility management entities (MMEs) may collect another type of PCMD data, and serving gateways (SGWs) may collect yet another type of PCMD data. The collected data can then be stored in the network element until it is needed by a post-processing tool. Records of the stored data are therefore labeled by an indicator of the identity of the user equipment. However, each of the collecting entities uses a different user equipment identifier. For example, an MME uses an International Mobile Subscriber Identity (IMSI) to uniquely identify the user equipment, whereas the eNodeBs are unaware of the IMSI and instead they use a negotiated temporary identifier that is associated with each user equipment for the duration of the call session with the eNodeB.
User equipment can also roam through numerous areas served by different eNodeBs, MMEs, and/or other network elements that can collect PCMD data. Consequently, the post-processing tool has to search through information stored on all of the network elements that collect PCMD data within the network when the post-processing tool wants to begin analyzing the PCMD data for one or more users. Locating the per-user information collected by the different network elements is a nontrivial task because typical wireless communication system may include thousands of eNodeBs and tens or hundreds of MMEs and SGWs. The problem is exacerbated by the fact that the different network elements use different identifiers for the same user equipment and some of these identifiers are temporary identifiers that may be released from their association with user equipment when the user equipment ends a particular connection.
Furthermore, the PCMD records collected by a network element for each user during the each time interval have to be correlated with the records collected by the other network elements so that the post-processing tool can analyze the records for each user equipment as a single record. Correlating the per-user information collected by the different network elements is a nontrivial task because the records collected by the different network elements may not be coordinated. For example, in the 3GPP standards, as many as three network elements can generate PCMD records for the same user and the network elements may generate the records at slightly different times. Hence, correlation of these records for the same user connection can be difficult to achieve. Again, the use of different identifiers by different network elements further complicates this task.
Storing the collected information may also present difficulties. For example, it is typical for each network element to deposit PCMD records on a host collector. Depositing per-user data collected for millions of users by thousands of eNodeBs, tens or hundreds of MMEs, and similar numbers of other network elements can easily overwhelm the capacity of even a large number of host collectors. Hence, another issue to cope with is the generation of a multiplicity of files on the host collector and the disk storage capacity required to store multiple files for the same user connection to the network.
Wireless providers that want to initiate (or terminate) PCMD data collection are also faced with the problem of signaling their intent to large numbers of network elements. For example, a wireless provider may want to turn ON the data collection functionality for a certain period of time and then they may want to turn OFF the data collection. Typically, PCMD collection is controlled by Element Management Systems that utilize management interfaces to each and every Network Element to turn ON PCMD or to turn it OFF. However, as discussed herein, a typical 4G LTE Wireless Network can have thousands of individual elements, which may require multiple Element Management Systems. Coordination of the data collection among several Element Management Systems may be difficult to achieve.